cannot ping myself

[root@SHK11AP12 ~]# ifconfig
eth0: flags=4163 mtu 1500
inet 172.16.170.191 netmask 255.255.255.0 broadcast 172.16.170.255
ether 00:15:5d:d0:b5:0a txqueuelen 1000 (Ethernet)
RX packets 18368 bytes 1264582 (1.2 MiB)
RX errors 0 dropped 8654 overruns 0 frame 0
TX packets 1434 bytes 214898 (209.8 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 12 bytes 1008 (1008.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 12 bytes 1008 (1008.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

[root@SHK11AP12 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
171.16.170.191 SHK11AP12 SHK11AP12.srl-hk.intra.net

[root@SHK11AP12 ~]# ping SHK11AP12
PING SHK11AP12 (171.16.170.191) 56(84) bytes of data.
^C
--- SHK11AP12 ping statistics ---
5 packets transmitted, 0 received, 100% packet loss, time 4133ms

[root@SHK11AP12 ~]# ping 17.16.170.191
PING 17.16.170.191 (17.16.170.191) 56(84) bytes of data.
^C
--- 17.16.170.191 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2069ms

any clues ? thanks in advance